Worm parasite may hold clues in bid for illness and allergy cures

November 7, 2005

Tiny worms that can trick the body’s natural defences could hold the key to new treatments for a range of conditions, including diabetes, asthma and hay fever. University of Edinburgh scientists, who have discovered that helminth parasites can exploit an ‘Achilles heel’ in our immune system, now hope to mimic the worms’ survival tactics in a bid to beat infection.

To find out how helminths fool the body’s defences, the team are focusing on the role played by so-called ‘regulatory cells’, which fulfil a policing role that protects our bodies. These cells decide when to stop the immune system from attacking the body’s own proteins (a process called autoimmunity) and also prevent it from attacking harmless environmental molecules.

It is thought that helminths produce molecules that trigger a response in regulatory cells (similar to the one that prevents autoimmunity), which tricks the body into switching off the response that would otherwise kill the parasites. If that is the case, then infections could be cured, not by vaccination or drug treatment, but by reactivating the immune system. It is the first time such a concept has been explored to curb the tropical diseases caused by helminths ““ such as filariasis and schistosomiasis ““ which affect one in four of the global population.

The study ““ the first findings of which are reported in the Journal of Experimental Medicine ““ could also help growing numbers of people in the developed world who have autoimmune conditions such as diabetes, asthma and hay fever. Again, the key is identifying the molecules that helminths produce in order to influence regulatory cell activity. If scientists can understand how these molecules trigger suppression of the immune system, they might also employ the molecules to stop the immune system from attacking the body’s own cells ““ which is what happens in diseases caused by over-active immune responses.

Professor Rick Maizels, of the University of Edinburgh’s School of Biological Sciences, has been awarded £1.3 million by the Wellcome Trust to conduct the research. He said: “Perhaps we can borrow a trick from parasites, and employ the molecules which suppress the immune system to treat these auto-immune disorders. The project therefore offers potential for new treatments of diseases in both the developed world and the disadvantaged countries of the tropics.”